#include <stdio.h>  
#include <stdlib.h>  
#include <string.h>  
#include <unistd.h>  
#include <arpa/inet.h>  
#include <sys/socket.h>  
  
#define BUF_SIZE    1024  
  
void error_handling(char *message);  
  
int main(int argc, char *argv[]){  
    int serv_sock,clnt_sock;  
    char message[BUF_SIZE];  
    int str_len,i;  
    struct sockaddr_in serv_adr;  
    struct sockaddr_in clnt_adr;  
    socklen_t clnt_adr_sz;
    FILE * readfp;
    FILE * writefp;
  
    if(argc != 2){  
        printf("Usage : %s <port>\n",argv[0]);  
        exit(1);  
    }  
  
    serv_sock = socket(PF_INET,SOCK_STREAM,0);  
    if(serv_sock == -1){  
        error_handling("socket() error");  
    }  
  
    memset(&serv_adr,0,sizeof(serv_adr));  
    serv_adr.sin_family=AF_INET;  
    serv_adr.sin_addr.s_addr=htonl(INADDR_ANY);  
    serv_adr.sin_port=htons(atoi(argv[1]));  
  
    if(bind(serv_sock,(struct sockaddr*)&serv_adr,sizeof(serv_adr)) == -1){  
        error_handling("bind() error");  
    }  
    
    if(listen(serv_sock,5) == -1){
	error_handling("listen error");
    }

    clnt_adr_sz = sizeof(clnt_adr);  
    for(i=0;i<5;i++){  
     	clnt_sock = accept(serv_sock,(struct sockaddr*)&clnt_adr,&clnt_adr_sz); 
	if(clnt_sock == -1){
	    error_handling("accept error");
	}else{
	    printf("connected client %d %d\n",i+1,clnt_sock);
	}

	readfp = fdopen(clnt_sock,"r");
	writefp = fdopen(clnt_sock,"w");
	
	while(!feof(readfp)){
	    fgets(message,BUF_SIZE,readfp);
	    fputs(message,writefp);
	    fflush(writefp);
	}
 
	printf("disconnected client %d \n",clnt_sock);	
	fclose(readfp);
	fclose(writefp); 
    }  
  
    close(serv_sock);  
  
    return 0;  
  
}  
  
void error_handling(char *message){  
  
    fputs(message,stderr);  
    fputs("\n",stderr);  
    exit(1);  
}  
